Interferometric modulators, such as the iMoD™, modulate light by controlling the self-interference of light that strikes the front surface of the modulator. These types of modulators typically employ a cavity having at least one movable or deflectable wall. This deflectable wall moves through planes parallel to the front wall of the cavity-the wall that is first encountered by light striking the front surface of the modulator. As the movable wall, typically comprised at least partly of metal and highly reflective, moves towards the front surface of the cavity, self-interference of the light within the cavity occurs, and the varying distance between the front and movable wall affects the color of light that exits the cavity at the front surface. The front surface is typically the surface where the image seen by the viewer appears, as interferometric modulators are usually direct-view devices.
The movable wall moves in response to an actuation signal generated by addressing circuitry that sends the signal to the movable element. The addressing circuitry is generally manufactured off-chip from the array of movable elements. This is in part because the substrate upon which the interferometric modulators are manufactured is transparent, such as plastic or glass.
Thin film transistors may be manufactured on transparent substrates. Integrating thin film transistors with the interferometric modulator array may provide an interferometric modulator with extended functionality.